Hot Flash Frequency and Blood Pressure: Data from the Study of Women's Health Across the Nation

Background: Vasomotor symptoms (VMS) are highly prevalent among midlife women and have been associated with subclinical cardiovascular disease (CVD). However, the association between VMS frequency and risk factors such as hypertension (HTN) remains unclear. Materials and Methods: We examined VMS frequency and blood pressure (BP) among 2839 participants of the Study of Women's Health Across the Nation (SWAN), a multiethnic, prospective, study of women enrolled from seven U.S. sites between November 1995 and October 1997. Women were age 42-52, with no history of CVD, and not postmenopausal at baseline. VMS was defined by the number of days a woman reported VMS over the 2-week period before each annual visit. Frequent VMS was defined as >= 6 days of VMS; less frequent VMS was defined 1-5 days of symptoms with asymptomatic women the reference group. BP was measured at each visit in addition to demographic and clinic factors. Results: At baseline, 298 women reported frequent VMS, 794 less frequent VMS and 1747 no VMS. More frequent baseline VMS was associated with higher BP. Compared to no VMS, baseline VMS was associated with HTN (odds ratio [OR] 1.47, 95% confidence interval [CI]; 1.14-1.88 for infrequent VMS, and OR 1.40, (95% CI; 0.97-2.02 for frequent VMS). Risk for incident pre-HTN or HTN during follow-up was increased among women with frequent VMS (hazard ratio of 1.39, 95% CI; 1.09-1.79) after adjustment for multiple covariates. Conclusion: Women with VMS may be more likely to develop HTN compared to women without VMS. Further research related to VMS including frequency of symptoms is warranted.